The performance of non-volatile memory systems has improved over the past several years. Changes in technology management have pushed the non-volatile memory devices into cameras, computers, personal data assistants, smart phones, and proprietary business applications.
The current flash memory devices, based on charge storage technologies, have limited life spans due to damage of the charge storage layers during writes. The damage can be caused by physical weakening of the crystal structure used to store the charge. This condition is countered by limiting the number of writes and reads that an individual memory cell can undergo and balancing writes across all of the locations in the memory. The limited reliability of the cells has given rise to error correction strategies and distributed write operations in order to extend the useable life of the memory modules. Many maintenance processes can operate in background without the knowledge of the operator.
Other non-volatile memory technologies are in development that can increase the useable memory density while extending the lifetime reliability of the memory structures. These non-volatile memory technologies include spin transfer torque random access memory (STT-RAM) and resistive random access memory (R-RAM™).
In order to improve the reliability of the non-volatile memories, manufacturers have investigated storage element material changes. These material changes can trade-off performance versus reliability. A satisfactory solution has not yet been found that can meet performance expectations and maintain reliable operation over a suitable component lifetime.
These emerging memories often utilize new material and new structure. An issue that has arisen in the new R-RAM™ technology is that the layers of the storage cells can delaminate due to their different expansion/contraction characteristics. The delamination can cause a pseudo high resistance state regardless of the written state of the storage cells. Since the delamination issue is a regional problem and the storage cell geometry is very small, a delamination of the layers can damage hundreds or thousands of the storage cells in a single region.
Thus, a need still remains for a non-volatile memory system that can withstand aggressive thermal cycling and reliability testing. In view of the exponential growth in the use of non-volatile memory in personal electronic devices, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.